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<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>使⽤正则表达式，测试⼀段字符串是否包含字⺟下划线和数字。</title>
</head>

<body>
  <script>

    var a = /[A-Z-a-z-0-9-_]/
    console.log(a.test('111ooo'));
  </script>
</body>

</html>